Detection and identification (or at least classification) of unknown substances have long been of great interest and have taken on even greater significance in recent years. Among methodologies that hold particular promise for precision detection and identification are various forms of spectroscopy. Spectroscopy may be used to analyze, characterize and identify a substance or material using one or more of an absorption spectrum, a scattering spectrum and an emission spectrum that results when the material is illuminated by a form of electromagnetic radiation (e.g., visible light). The absorption, scattering and emission spectra produced by illuminating the material determine a spectral ‘fingerprint’ of the material. In general, the spectral fingerprint is characteristic of the particular material to facilitate identification of the material. Among the most powerful of optical emission spectroscopy techniques are those based on Raman scattering.
Scattering spectroscopy is an important means of identifying, monitoring and characterizing a variety of analyte species (i.e., analytes) ranging from relatively simple inorganic chemical compounds to complex biological molecules. Among the various types of scattering spectroscopy are methodologies that exploit Raman scattering and emission due to fluorescence (e.g., fluorescence emission) from an analyte. In general, scattering spectroscopy employs a signal (e.g., optical beam) to excite the analyte that, in turn, produces a response or scattered or emitted signal that is dependent on a characteristic (e.g., constituent elements or molecules of) the analyte. By detecting and analyzing the scattered or emitted signal (e.g., using spectral analysis), the analyte may be identified and even quantified, in some instances.
Certain examples have other features that are one of in addition to and in lieu of the features illustrated in the above-referenced figures. These and other features are detailed below with reference to the above-referenced figures.